Method and system for a single-fed patch antenna having improved axial ratio performance

Abstract

A micro-strip antenna includes a conducting ground plane and a dielectric substrate mounted above the conducting ground plane. A patch element is mounted above the dielectric substrate and configured to produce an antenna pattern. The antenna pattern is formed by a number of linear polarization components. The patch element includes a single feed point extending through the conducting ground plane and the dielectric substrate. Two or more notches within the patch element are configured to perturb each of the linear polarization components.

1 . A patch antenna comprising: 
 a ground plane;    a conductive patch element having a substantially circular shape, said patch element including at least two notches disposed substantially symmetrically in a circumferential edge of said patch element; and    a dielectric layer disposed between said ground plane and said patch element to form said patch antenna.    
   
   
       2 . A micro-strip antenna, comprising: 
 a conducting ground plane;    a dielectric substrate mounted on the conducting ground plane;    a patch element mounted on the dielectric substrate and configured to produce an antenna pattern formed by a number of linear polarization components; and    at least two notches formed within the patch element and configured to perturb each of the linear polarization components.    
   
   
       3 . The micro-strip antenna of  claim 2 , wherein the patch element includes only a single feed point, extending through the conducting ground plane and the dielectric substrate.  
   
   
       4 . The micro-strip antenna of  claim 3 , wherein the single feed point is formed about half way between a center of the patch element and an outer circumference thereof.  
   
   
       5 . The micro-strip antenna of  claim 2 , wherein the two notches are substantially symmetrical along x and y axes and substantially parallel with one another.  
   
   
       6 . The micro-strip antenna of  claim 2 , wherein the notches are substantially rectangular.  
   
   
       7 . The micro-strip antenna of  claim 2 , wherein the patch element is substantially annular.  
   
   
       8 . The micro-strip antenna of  claim 2 , wherein the patch element has a radius within a range of about 120 to 130 mils; and wherein the notches have a depth within a range of about 70 to 80 mils.  
   
   
       9 . The micro-strip antenna of  claim 8 , wherein the notches are separated from one another by a distance within a range of about 8 to 12 mils.  
   
   
       10 . The micro-strip antenna of  claim 9 , wherein the single feed point is about 45 degrees from a radial line formed by the notches.  
   
   
       11 . A method for enhancing polarization purity of a circularly polarized signal radiated from a single fed patch antenna, comprising: 
 receiving a radio frequency (RF) signal in a port of the patch antenna;    converting the received RF signal to electromagnetic energy having first and second linearly polarized energy components; and    introducing at least two impedance loads to at least one of the first and second linearly polarized energy components.    
   
   
       12 . The method of  claim 11 , wherein each load perturbs a corresponding one of the first and second linearly polarized energy components.  
   
   
       13 . The method of  claim 12 , wherein the first and second linearly polarized energy components respectively represent left hand and right hand circularly polarized components.  
   
   
       14 . The method of  claim 13 , wherein the electromagnetic energy includes an electric current.  
   
   
       15 . An apparatus for enhancing polarization purity of a circularly polarized signal radiated from a single fed patch antenna, comprising: 
 means for receiving a radio, frequency (RF) signal in a port of the patch antenna;    means for converting the received RF signal to electromagnetic energy having first and second linearly polarized energy components; and    means for introducing two or more impedance loads to at least one of the first and second linearly polarized energy components.    
   
   
       16 . The patch antenna of  claim 1 , wherein the conductive patch element includes only a single feed point extending through the conducting ground plane and the dielectric substrate.  
   
   
       17 . The patch antenna of  claim 16 , wherein the single feed point is formed about half way between a center of the patch element and an outer circumference thereof.  
   
   
       18 . The patch antenna of  claim 1 , wherein the two notches are substantially symmetrical along x and y axes and substantially parallel with one another.  
   
   
       19 . The patch antenna of  claim 1 , wherein the notches are substantially rectangular.  
   
   
       20 . The patch antenna of  claim 1 , wherein the patch element is substantially annular.